While uploading a partlist with old IDs (pre-part variant merge), the parts with
IDs that changed cause the partlist to fail import. While it's annoying to
go through the XML to correct these errors, it's at least a solution. However,
it feels like a huge missed opportunity to not be backwards compatible at all.
The upload tool should either automatically correct these errors or to at least
suggest the corrections.
However, more egregious is that when you import such a partlist into Studio as
a part palette, the import silently ignores these old part IDs without giving
any error or warning. The parts will just be missing from the palette, causing
confusio
since updates from bricklink are super slow/never happen for some things the
best workaround is to first upload the file into brickstore which will then update
all the numbers and then you can redownload the file and it should work properly